The present invention relates to a manufacturing process for a field emission device. More particularly, it relates to a method of fabricating a field emission device having a chimney-shaped emitter for increasing emission area, thereby being suitable for application to a flat panel display.
Field emission devices are typically manufactured by the method set forth by C. A. Spindt in 1968. However, Spindt""s method does not use standard integrated circuit (IC) techniques. Complicated equipment such as an oblique-angle evaporator for depositing a lift-off layer are required using Spindt""s method to fabricate a field emission device. Another method for manufacturing a field emission device utilizing IC techniques uses silicon material as an emitter and may produce emitter tips using an oxidation sharpening method. Field emission devices manufactured by this method can be fabricated easily and at low cost. However, the method is carried out at a high temperature. Thus, field emission devices produced by this method cannot be applied to a flat panel display having a large area.
In view of the above disadvantages, an object of the invention is to provide a method of fabricating a field emission device, which can be fabricated by standard IC techniques and equipment.
Another object of the invention is to provide a method of fabricating a field emission device, which can be fabricated at a temperature below 400xc2x0 C.
The above objects are attained by providing a first method of fabricating a field emission device (diode-type) on a semiconductor substrate, comprising the steps of: (a) forming an insulating layer over said semiconductor substrate; (b) selectively etching said insulating layer to form an insulating structure having a hole exposing the surface of said semiconductor substrate; (c) depositing a conductive layer on the upper surface and sidewalls of said insulating structure; (d) etching back said conductive layer, thereby leaving a chimney-shaped conductive emitter remaining on said sidewalls of said insulating structure; and (e) wet etching a portion of said insulating structure so that the upper surface of said insulating structure is lower than that of said emitter.
The above objects are attained by providing a second method of fabricating a field emission device (triode-type) on a semiconductor substrate, comprising the steps of: (a) sequentially forming a first insulating layer, a conductive layer for a gate, and a second insulating layer over said semiconductor substrate; (b) selectively etching said second insulating layer, said conductive layer, and said first insulating layer to form a stack structure having a hole exposing the surface of said semiconductor substrate; (c) forming an insulating spacer on the sidewalls of said stack structure; (d) forming a conductive spacer as a field emitter onto said insulating spacer; and (e) wet etching said second insulating layer and the top of said insulating spacer so that the upper surface of said insulating spacer is lower than that of said emitter.